The use of synthetic fungicides to control phytopathogenic fungi in crops is a wide spread practice. This practice has gained a high degree of commercial success because it has been shown that such control can increase crop yield. Fungicides can be applied directly to plant propagation materials (such as seeds) prior to sowing and/or are used in foliar or furrow applications.
Seed treatments are used on a large variety of crops to control a large variety of pests. Seed treatments are commonly used to ensure uniform stand establishment by protecting against soilborne diseases and insects. Systemic seed treatments may provide an alternative to traditional broadcast sprays of foliar fungicides or insecticides for certain early season airborne diseases and insects.
In general, fungicidal seed treatments are used for three reasons: (1) to control soil-borne fungal disease organisms (pathogens) that cause seed rots, damping-off, seedling blights and root rot; (2) to control fungal pathogens that are surface-borne on the seed, such as those that cause covered smuts of barley and oats, bunt of wheat, black point of cereal grains, and seed-borne safflower rust; and (3) to control internally seed-borne fungal pathogens such as the loose smut fungi of cereals.
Fungicide seed treatments come in a variety of formulations: dry flowables (DF), liquid flowables (LF), true liquids (TL), emulsifiable concentrates (EC), dusts (D), wettable powders (WP), suspoemulsions (SE), water-dispersible granules (WG) and others. Some are registered for use only by commercial applicators using closed application systems, others are readily available for on-farm use as dusts, slurries, water soluble bags, or liquid ready-to-apply formulations.
Commercial seed treatment is often desirable due to the specialized equipment required to properly apply treatments or to treat large volumes of seed. An important concern of the commercial treater is equipment performance to ensure the delivery of a proper amount of active ingredient to the seed. This has become especially important with more modern fungicides that require only very small amounts of material (down to 1 g active ingredient per hundred weight of seed).
Conveniently, many seed treatment materials also are available for on-farm use. These are known as hopper-box or planter-box treatments wherein liquid or dry formulations are applied to seed as it passes through an auger from the transport bin or truck to the planter boxes. These formulations are a very convenient way to apply seed treatment onto bulk seed right before planting. Conventional dry treatments generally are formulated with talc or graphite which adheres the treatment chemical to the seed. Conventional liquid hopper-box treatments generally are made available as a fast-drying formulations. In any case, good seed coverage is required for maximum benefit from any seed treatment formulation.
However, obtaining thorough seed coverage can be difficult when attempting to treat seed. For example, dry formulations can present unacceptable worker exposure to the fungicidal active ingredient. Certain liquid formulations can become inhomogeneous on storage, such that particle size or viscosity do not remain constant. Additional problems can arise such as unacceptable drying times, material build-up in the seed treater, low seed flowability, poor seed coverage and dust-off of the fungicide from the seed prior to planting. As a result, handling is rendered difficult and the biological efficacy of the seed treatment is reduced.
There is a need in the art for alternative new liquid fungicidal seed treatment compositions that are effective for use with both commercial and on-farm seed treatment equipment.